I'm using Thunderbird 115.10.1 and Windows 11 Pro. Thunderbird has suddenly started sending my partner's emails to Trash. We've been emailing fine for years before this. She has not changed anything in her emailing. I've closed and re-opened Thunderbird. Her emails are not marked as Spam and I have marked some of them as 'not junk'. Anyone got any ideas? I can't seem to find reference to other people having this problem.

PS It's only her emails this is happening to. All other valid ones are OK.

PPS her emails are from a Gmail account but emails from other people with Gmail accounts don't go to Trash.

Did you happen to have any message filters setup that copied or moved her emails to a particular folder? If so, might make sure it's not sending it to trash now all of a sudden.

Unless there's some message filter acting on them, I would expect them to stay in the Inbox.

That's a fair point Mark, but no, in this case there are no filters testing for any part of her email address.